Selective layering of superabsorbents in meltblown substrates

ABSTRACT

The invention generally provides for formation of meltblown material containing wood fiber on to a continuous foraminous belt. During formation a polymer and wood fiber first layer is applied to a moving belt from at least one bank of meltblown forming apparatus. This first layer does not contain superabsorbent. The belt carrying the first layer passes beneath at least one further source of meltblown fiber into which superabsorbent is added along with the wood fibers. This provides at least one additional layer integrally connected to the first-formed layer and having superabsorbent properties. The first layer acts to aid in trapping of any superabsorbent which is not immediately entangled in the meltblown and wood fibers and prevents it passing through the forming belt.

This is a dimensional of co-pending application Ser. No. 835,009 filedon Apr. 28, 1986, now U.S. Pat. No. 4,655,757, which is a division ofU.S. Ser. No. 602,993 filed Apr. 23, 1984, now U.S. Pat. No. 4,604,313.

TECHNICAL FIELD

This invention relates to nonwoven fabrics and in particular thosecomprising a matrix of meltblown polymer fibers and more particularly toa wood pulp containing nonwoven fabric which additionally contains aparticulate superabsorbent material.

BACKGROUND ART

It is known to form blown fibers of polyolefin such as polyethylene orpolypropylene. Such meltblown fibers are known for use in wipes andother disposable items.

It is also been known as disclosed in U.S. Pat. No. 4,100,324 Andersonet al. to form nonwoven fabric materials of long thermoplastic polymermicrofibers that have entangled therein wood pulp fibers. Such materialshave found use in wipes and as absorbent materials for feminine care andincontinent products.

It has been suggested in the British Patent Application Publication No.2,113,731 of Aug. 10, 1983, that the meltblown fiber having wood pulpfibers may be further supplied during forming with another absorbentmaterial such as a superabsorbent or clay material. It is disclosed inthe above United Kingdom Patent Application Publication that powderedsuperabsorbent may be added to the meltblown material during formationand that the majority of the particles will be entrapped into thematerial as it is gathered on a forming surface. The addition ofsuperabsorbent particles to meltblown materials has also been suggestedin U.S. Pat. No. 4,429,001--Koplin et al.

The use of superabsorbents in combination with fibrous material in anabsorbent garment has been suggested by U.S. Pat. No. 4,338,371 Dawn etal. in which a layer of superabsorbent material containingsuperabsorbent is provided in a garment for utilization by astronautsfor extravehicular activity. U.S. Pat. No. 4,297,410 Tsuchiya et al.also discloses a structure wherein a superabsorbent layer is placedbetween nonwoven fabric layers.

There have been several difficulties in prior materials utilizingsuperabsorbents. One difficulty has been that the superabsorbentmaterials exhibit a phenomenon usually refered to as gel-blocking. Whenthis occurs the superabsorbents that are first exposed to liquids swelland block access of the liquid to the remaining superabsorbent. Apreferred present practice attempts to overcome the gel blockingphenomenon by sandwiching either particulate or film forms ofsuperabsorbent between tissue or similar materials. This technique,however, tends to restrict the uptake of fluids by the superabsorbents,and adds cost to the superabsorbent material. Another difficulty withmany superabsorbent containing materials is that the hydrogelsuperabsorbents when wet have an uncomfortable, clammy, slimy feel tothem. The use of these materials in applications in which they areexposed to the body has been particularly difficult due to the slimy,unpleasant feel. There also has been difficulty in the processes inwhich air-forming is used in combination with particulatesuperabsorbents. Air-forming processes require the removal of air frombeneath the forming surface. During air removal the particulatesuperabsorbents tend to also be removed as they are primarily held byphysical entanglement and are not chemically bound with the meltblownthermoplastic fibers. The difficulties caused by sliminess have beenattempted to be overcome by effectively burying the superabsorbentcontaining ply(s) beneath one or more plies that do not containsuperabsorbent material.

Therefore, there is a need for an improved combination of superabsorbentmaterial and fibrous material in which gel-blocking is miniminal andsuperabsorbent is not wasted (by passing through the forming process,and being caught by the dust collector), and costly plying to mask theclammy, slimy feel of superabsorbent materials is unnecessary. There isalso a need for a nonwoven fibrous material that acts as a matrix inwhich the particulate superabsorbents may be easily accessible to fluidsand may be free to expand.

DISCLOSURE OF THE INVENTION

An object of this invention is to form a superabsorbent containingnonwoven fibrous material that does not present a slimy surface whenwet.

An additional object of this invention to form a nonwoven fibrousmaterial without a substantial loss of superabsorbent particulate duringformation.

A further object of this invention is to form an absorbent nonwovenfibrous material that presents a drier feeling surface after fluidabsorption.

These and other objects of the invention are generally accomplished byproviding for formation of meltblown polymer material containing wood orother staple fiber and superabsorbent on a continuous forming wire orother foraminous belt. During formation a first layer of polymer fibersand entangled wood or other staple fibers is applied to the moving wirefrom at least one bank of meltblown fiber forming apparatus. This firstlayer does not contain superabsorbent. The wire carrying the first layerpasses beneath at least one further source of meltblown fiber into whichsuperabsorbent is added along with the wood or other staple fibers. Thisprovides at least one additional layer integrally connected to thefirst-formed layer and having superabsorbent properties. The first layeracts to aid in trapping of any superabsorbent which is not immediatelyentangled in the meltblown and wood fibers and prevents its passingthrough the forming belt. The first layer also is the preferred bodyside in use as it will not be slimy and will feel drier than thesuperabsorbent containing side.

In a preferred form a single layer of air-formed meltblown fibercontaining wood fibers is placed onto a moving forming wire and thenpassed beneath a second air stream containing a combination of meltblownpolymer fibers, wood fibers and superabsorbent. The second bank forms asuperabsorbent-containing layer that will be integrally connected to thefirst-formed layer, thereby forming a composite material that has itslayers integrally connected and presents a cloth-like surface on oneside and a superabsorbent-containing surface on the other. Therefore,this allows the placement of the cloth-like surface towards the skin ofthe wearer while the superabsorbent-containing surface is on theinterior of the material during use as a dressing or incontinentproduct.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a device of the invention having two banks forformation of meltblown fibers with the downstream bank additionallyhaving provision for application of superabsorbent material.

FIG. 2 has illustrates of a belt-forming unit for meltblown materials inwhich three banks for formation of meltblown material are shown.

FIG. 3 illustrates a cross-section of a two-layer superabsorbentcontaining nonwoven of the invention.

FIG. 4 is a cross-section of the material formed by the process andapparatus of FIG. 2.

FIG. 5 illustrates an alternate embodiment of the invention in which theabsorbent layer structure of the invention is provided with embossingand combined with a carrier sheet.

FIG. 6 illustrates a three-layered structure in accordance with theinvention in which the middle layer contains superabsorbent.

FIG. 7 is a view of a dressing formed from the absorbent material of theinvention.

FIG. 8 is a cross-section of the dressing of FIG. 7 taken on line 8--8of FIG. 7.

MODES FOR CARRYING OUT THE INVENTION

The invention has numerous advantages over prior products and methodsfor combination of superabsorbents with other carrier and absorbentmaterials. In the invention the superabsorbent is carried in an integralstructure in such a way that the superabsorbent will not contact theskin when the structure is utilized in a dressing, diaper, orincontinent product. The prevention of skin contact has the advantagethat the slimy and clammy feel of wet superabsorbent is not felt, andfurther, the superabsorbent will not cause irritation to the skin of thewearer. Another advantage is that the particulate superabsorbent isgenerally encased within the dressing, garment or other absorbentproduct such that any particles that become loose are retained in theproduct rather than leaving the surface. If the absorbent particlesleave the surface they, of course, are not available for absorbency, andfurther cause the product to be considered undesirable as the powder isannoying to the wearer or person manipulating the absorbent device.

Another advantage of the system of the invention is that during theforming process the superabsorbent is not removed by the air-removalsystem in an excessive amount. If applied in the first layer ofmeltblown and wood or staple fibers directly at the forming wire, asignificant quantity of powdered superabsorbent will pass through and beremoved by the air-forming system. This particulate is generally wastedas it is not recoverable efficiently. These and other advantages of theinvention will be apparent from the detailed description provided below.

FIG. 1 illustrates the forming apparatus generally indicated as 10 whichis composed of two meltblown units 20 and 21, and a movable foraminousbelt apparatus 23. The foraminous belt is preferably a wire belt. Themeltblown apparatus 20 is composed of a die head 22 through which airstreams 24 and 26 pass. Supply and delivery device 28 delivers polymerto extruder 30 for delivery to the die head 22. The polymer leavesextruder head 22 and is combined with primary air stream 32, where thefine polymer streams leaving the die head 22 are attenuated by theconverging flows of high velocity heated gas (usually air) suppliedthrough nozzles 24 and 26 to break the polymer streams intodiscontinuous microfibers of small diameter. The die head preferablyincludes at least one straight row or extrusion apertures. In general,the resulting microfibers have an average fiber diameter of up to onlyabout 10 microns with very few, if any, of the microfibers exceeding 10microns in diameter. In general, the average diameter of the microfibersis usually greater than about 1 micron and within the range of about 2to about 6 microns, often averaging about 5 microns. While themicrofibers are predominately discontinuous, they generally have alength exceeding that normally associated with staple fibers.

The primary gas stream 32 is merged with a secondary gas streamcontaining individualized wood pulp or other staple fibers so as tointegrate the two different fibrous materials in a single step. Theindividualized wood pulp fibers typically have a length of about 0.5 to10 millimeters and a length to maximum width ratio of about 10 to 1 to400 to 1. A typical cross-section has a irregular width of 10 micronsand a thickness of 5 microns. In the illustrated arrangement a secondarygas stream 40 is formed by a pulp sheet divellicating apparatus of thetype described in U.S. Pat. No. 3,793,678 to Appel. This apparatuscomprises a conventional picker roll 42 having picking teeth fordivellicating pulp sheets 44 into individual fibers. The pulp sheets 44are fed radially along a picker roll radius to the picker roll 42. It isthe teeth of the picker roll 42 that allocate the pulp sheets 44 intoindividual fibers, the resulting separated fibers are conveyed towardthe primary air stream 32 through a nozzle or duct 48. A housing 50covers the picker roll 42. A passageway 52 provides process air to thepicker roll in sufficient quantity to provide a medium for conveying thefibers through the forming duct 48 at a velocity approaching that of thepicker teeth. The air may be supplied by conventional means, i.e., ablower not shown. It has been found that in order to avoid fiberflocking, the individual fibers should be conveyed through the duct 48at substantially the same velocity at which they leave the picker teethafter separation from the pulp sheets 44. The apparatus described forformation of the article of microfibers having wood fibers entangledtherein now referred to as coform is known and is more fully describedin U.S. Pat. No. 4,100,324 Anderson et al. which is incorporated hereinby reference. Air stream 32 having wood fibers from stream 48incorporated therein then is placed onto a moving belt 60 that passesbeneath the forming die 22 as the microfibers and air stream aredirected downwardly. The foraminous belt 60 is provided with suctionboxes 62 and 64 driven by blowers 66 and 68 that withdraw air frombeneath the foraminous belt 60 and provide for uniform laydown of thefibers onto the belt. Belt 60 in addition to being supported by roll 61is also supported by roll 63. While illustrated with two suctiondevices, the number and size of the suction devices below the belt maybe varied. Further, the forming device is provided with dust collectordevices, not shown, to prevent escape of superabsorbent and fibers tothe atmosphere.

As illustrated in FIG. 1, a meltblowing device 20 lays down a layer ofmeltblown polymer fibers having wood or other staple fibers entangledtherein as layer 70. This passes beneath the second meltblowing device21 where a second layer 72 is placed thereon and joined to the layer 70.Layer 72 is formed by device 21 that is composed of an extruder 74 fedby material supply device 77. Extruder 74 feeds to die head 76 that isgenerally similar to die head 22, having high velocity air nozzles forsupplying air to extrusion stream 82. As the air streams from nozzle 78and 80 merge into stream 82 and entrain the extruded fibers, they aremeltblown into microfibers and mixed with a stream of wood fibers 84,exiting through nozzle 86 from the picker device 88. In picker device 88the picker roll 90 rotates and divellicates pulp sheets 92 as they areunrolled from supply roll 94. The pulp sheets are divellicated andpassed through nozzle 86 to join the meltblown stream 82. Process air issupplied through duct 98 of the picker roll housing 88. The meltblownextrusion device 21 differs from that of 20 in that there additionallyis provided a source of superabsorbent material generally indicated asapparatus 100 composed of storage hopper 102, having a feed device 104leading to a source of high velocity air 106, and a nozzle or duct 108providing a stream of superabsorbent 110 to the meltblown stream 82 at apoint slightly above the point where nozzle 86 provides a stream ofcellulose fibers 84. The superabsorbent is entrained with the meltblownfibers and the cellulose fibers. It then is laid onto the layer 70 at122 as layer 72. Suction box 64 aids in laydown. The fibers of thesecond layer when laid down become somewhat entangled with fibers on thesurface of first fiber layer 70. This entanglement is such that anintegral unit is formed, although if the layers 70 and 72 are pulledapart they will generally separate on the formation line. However, theentanglement is such that an integral structure for processing and usepurposes is formed. The composite structure of layer 72 and 70 afterleaving the support roller 61 may be further processed by known meanssuch as cutters and stackers, not shown. Belt 60 in addition to beingsupported by roll 61 is also supported by roll 63.

The apparatus of FIG. 2 is a modified form of the apparatus of FIG. 1 inwhich meltblowing devices 20 and 21, as previously described, are placedabove a foraminous belt 120 that is driven by rolls 122 and 124. Belowthe belt are located at least 3 suction devices 62, 64, and 126. Inaddition to meltblown devices 20 and 21, previously described, there isnow a third meltblown apparatus, device 130. This third device alsocomprises, as systems 20 and 21 do, an extruder 132 fed by supply device134, leading to extrusion head 136. The extrusion head 136 has thereintwo channels 138 and 140 that are provided with a source of subsonic airnot shown to provide a primary air stream 160 into which polymer isextruded by extrusion head 136. The primary air stream 160 havingentrained therein the meltblown fibers has added to it fiber cellulosefrom picker device 144. The picker device 144 is comprised of a pickerroll 146 that has a air channel 148 as a source of primary air to thepicker roll. The picker roll 146 divellicates pulp 150 that is suppliedfrom pulp roll 152. The divellicated fibers pass through nozzle orchannel 158 and are blown into the meltblown stream 141 as a stream offibers 142. Apparatus 130 also has a feed device 170 that is composed ofa storage device 172 for superabsorbent material. The storage device 172has a feeder 174 attached thereto that feeds into a source of subsonicair 176. The superabsorbent entrained in the subsonic air passes throughfeeder nozzle 178 and is applied to the polymer stream as a stream ofsuperabsorbent entrained in a tertiary air stream 180. In FIG. 2 thefirst layer laid down by device 20 is indicated as 190. The second layercontaining superabsorbent material is 192 and the third layer that issourced from apparatus 130 is laid down as layer 194. These layers areintegrally connected by entanglement of fibers at laydown. Thethree-layered sheet 196 after leaving the forming device may be treatedby conventional means such as cutters and stackers to prepare it for usein an absorbent product. It may be seen that the invention asillustrated in FIG. 2 is capable of forming nonwoven webs withsuperabsorbent in either or both of two upper layers or with only acenter section containing superabsorbent if the superabsorbent feeder170 is not operated.

FIG. 3 is illustrative of a cross-section through a integral two-layeredsheet such as formed by the process and apparatus as illustrated byFIG. 1. Layer 70 is composed of a tangled structure of wood or otherfiber and meltblown polymer fibers. Layer 72 is a tangled structure ofmeltblown fibers and wood fiber, in addition containing superabsorbentabsorbent particles 76. The area of joinder of the two layers at 74 issomewhat irregular as the fibers from each layer are somewhatintermingled and it is noted that some particles of superabsorbent suchas 78 have crossed into the lower layer drawn there by the vacuum effectof the suction below the foraminous belt during formation.

FIG. 4 is illustrative of a three-layered structure such as may beformed by the process and apparatus of FIG. 2. As illustrated in thecross-section, the layer 190 is formed of entangled polymer andcellulose fibers with only stray particles of superabsorbent such as191. Layers 192 and 194 are formed of tangled polymer fibers, cellulosefibers, and superabsorbent particles. The layers themselves havesomewhat intermingled surfaces and form an integral structure.

FIG. 6 illustrates an alternate embodiment of a nonwoven structure inaccordance with the invention. In FIG. 6 an integral body having threelayers 200, 202, and 204 is illustrated. Layers 200 and 204 are formedof entangled polymer and cellulose fibers while these surface layers areintegrally connected to a center layer 202 which is formed ofintermingled and intertwined cellulose fibers, polymer fibers andsuperabsorbent particles 206. This structure has the advantage that thesuperabsorbent material is not exposed on either surface. Therefore, inuse this structure will not present a slimy surface. Further, theshaking loose of superabsorbent particles is minimized as is thepossibility of allergic reaction caused by the handling of thesuperabsorbent containing nonwoven material.

FIG. 5 illustrates apparatus such as previously illustrated in FIG. 1but including varous optional peripheral devices that may be includedwith a forming system in accordance with the invention. A base sheet 210may be placed onto the foraminous belt 60 prior to application of thefirst meltblown fiber stream. The base sheet 210 ordinarily would be apervious sheet such as a spunbonded fabric sheet that would notinterfere with air flow through the belt 60. The pervious material wouldbe applied from roll 216 passing under applicator roll 218 onto the belt60. It may be desired that the strength of the composite web 220 beimproved by embossing ultrasonically as by an ultrasonic embossingstation comprising an ultrasonic calendering head 222 vibrating againsta patterned anvil roll 224. The embossing conditions as well as theembossing pattern may be selected to provide the desired characteristicsto the final product. In the preferred intermittent pattern it ispreferred that the area of the web occupied by the embossed area, afterpassing through the embossing nip, be about 5 to about 50 percent of thesurface area of the material, the particular embossing conditions forany given material will depend on the composition of the material. It isalso known to carry on embossing by the use of heated patternedembossing rolls. The embossing process lowers the absorbency of theproduct although it does increase strength and improve appearance. It isfurther possible to apply a top sheet 230 to the composite sheet 220.The top sheet may be either a pervious sheet, an impervious layer, oranother absorbent material. Top sheet 230 is applied from roll 232 underapplicator roll 234. It also may be desirable to apply a carrier orbottom sheet 240 beneath the composite 220. This sheet may beparticularly desirable if a forming sheet 210 is not used as it will aidin handling of the product and then may be discarded.

The dressing 250 of FIGS. 7 and 8 is formed with the absorbent materialof FIG. 3. The dressing 250 has an impervious polymer wrapping 254 and abody-side pervious member 252. The impervious wrapping is adhered to thepervious liner by glue lines at 256 and 258. The ends of the dressingare ultrasonicly sealed at 260 and 262. The coform material of layer 70that does not have superabsorbent is exposed to the body of the wearer.The dressing 250 may be utilized for absorption of any body exudate.Typical of such uses would be as catamenial devices, diapers, or wounddressings. A preferred use is in incontinent care devices as theabsorbent is capable of holding large amounts of liquid such as arereleased in an incontinent adult.

The product produced by the process and apparatus of the invention hasthe advantage as set forth above that the slimy superabsorbent will notbe presented to a bodily surface. It further has the advantage that whenthe composite of polymer fiber and cellulose fiber that overlays thesuperabsorbent layer is wet, the wetness will spread on the exposedsurface layer prior to being absorbed by the superabsorbent layer. Thisthen presents a drier surface to the wearer after the superabsorbentlayer has absorbed the liquid from the surface layer. The drier surfaceis also less likely to leak when compressed. The composite structurethen presents a drier feel than the layer of composite of microfilamentsof polymer and wood fiber as the wetness is absorbed by thesuperabsorbent integral layer with which it is in contact. Thecomposition of the meltblown layer containing cellulose fibers and thelayer containing meltblown, cellulose and superabsorbent may be variedover a wide range. The combination of air-formed meltblown polymer andcellulose fiber is commonly called coform. This material may varybetween about 10 percent polymer and 90 percent polymer and between 90percent cellulose and 10 percent cellulose. Generally, there is also asurfactant that is added to the product to aid in wetting of thepolypropylene.

The superabsorbent material suitable for the invention may be anysuperabsorbent that will maintain its particle integrity during themeltblowing process and exhibit good storage, handling, and resistanceto gel-blocking properties. Typical of such materials are thewater-insoluble hydrocolloidal particles derived from starches that willswell but not dissolve when exposed to water. Suitable for the inventionare those superabsorbents formed from hydrolyzed cross-linkedpolyacrylamides, polyacrylates, polymers of acrylic polymers, or theircopolymers. Such materials when lightly cross-linked are insoluble andwhen dry are solids that may be blown in an air stream. A preferredmaterial is a sodium polyacrylate hydrocolloidal particle such availablefrom Grain Processing Corporation as Waterlock J-500. The superabsorbentparticle may be of any desired shape such as fibrous or round, flakes orirregular.

The staple fiber blown into the coform may be any fiber that improvesthe absorbency or other property of the coform. Suitable fibers includepolyester fibers, nylon fibers, and cotton fibers. The preferred fiberis a wood fiber as the wood fibers formed from pulp are of desired size,low in cost, and of high absorbency.

In the structure of the invention superabsorbent may be added in anyamount from a very minimum to an upper range which would be the amountthat would stay in the composite without causing the composite to loseits integrity or the superabsorbent to be easily shaken loose. Asuitable amount of superabsorbent generally is between about 2.0 andabout 60 percent by weight of the layer containing the superabsorbent. Apreferred amount of superabsorbent is between about 5 percent and about22 percent by weight of the layer containing superabsorbent for highabsorbence and good fabric strength. The preferred superabsorbentcontaining coform layers has between about 11 and about 55 grams ofsuperabsorbent per square meter for a substrate that withoutsuperabsorbent would weigh about 100 grams/sq.meter. Generally thecoform portion is preferred to be in a range of about 70 percent pulpand about 30 percent polymer for high absorbency and good handlingproperties.

The invention has been described with the formation of coform material.It is also within the invention to form successive layers of air-formedmeltblown sheet material, not containing additional staple fibers, inwhich the first layer is without superabsorbent while the second orother successive layer does contain superabsorbent. The phrases"meltblown layer" and "meltblown sheet" as used herein mean anair-formed meltblown polymer fiber layer of entangled fibers notcontaining staple fibers whereas the term "coform" is a layer, aspreviously described, that contains staple fibers in addition tomeltblown fibers. The formation of air-formed entangled meltblown fibersheet materials with superabsorbents is described in U.S. Pat. No.4,429,001--Kolpin et al. and British Patent Application Publication No.2,113,731 of Aug. 10, 1983, both herein incorporated by reference.

The formation of layered meltblown absorbent structures in which theexposed body-side liner does not contain superabsorbent also would havethe advantages as in the coform structures of not exposing a slimysurface and also being less likely to lose superabsorbent particlesduring handling. A layered meltblown structure could be formed by theillustrated apparatus of the drawings of FIGS. 1, 2, and 5 by notoperating the wood pulp divellicating apparatus. In another alternativeembodiment, a structure of one or more coform layers in integralcombination with one or more meltblown layers is also possible. Any orall layers except the body-side or exposed layer could havesuperabsorbent. Coform structures are preferred over meltblown fiberlayers for most purposes as they are higher in absorbency.

A surface layer of only meltblown fibers with interior layers of coformwould have increased abrasion resistance and strength. A meltblowninterior layer containing superabsorbent and surface layer or layers ofcoform would have better holding of the superabsorbent powder in thearticle. The formation of various combinations of meltblown and coformlayers is within the invention as is the placement of superabsorbent ineither the meltblown or coform layer.

The superabsorbent containing product of the invention finds uses in avariety of fields. It is particularly suitable for use in products suchas perineal shields and undergarments for the incontinent. It has a veryhigh absorbency as well as the ability to retain fluids. It also has ahigh ability to transmit fluids from the point of application to otherportions of the garment where the fluid may be absorbed rather thanleaking from the garment. It also is suitable for bedpads, diapers,feminine care products, and for body dressings such as those for wounds.It is particularly desirable where high liquid absorbency is desired atrelatively low cost with good retention of superabsorbent duringhandling and no exposure of superabsorbent to the skin. The product alsoexhibits good retention of liquids in the composite sheet when the sheetis compressed or manipulated.

EXAMPLE

A composite fabric in accordance with the invention is prepared inaccordance with the general procedure described above and illustrated inFIG. 1. Polypropylene resin (PD 701--Hercules) is extruded from a seriesof orifices numbering approximately 1200 across a 60-inch width. Theextrusion rate is at about 5 pounds per inch per hour from each of the 2banks. The extrusion is at a final temperature of about 600° F. andfibers are attenuated in primary air streams flowing at a sonic velocityand a combined rate of about 900 SCFM at a temperature of about 600° F.The secondary air stream containing suspended pulp fluff is comprised ofSouthern pine bleached kraft with softening agents. The pulp is pickedand forced into a fiber jet approximately 11/2-2 inches from the primaryair stream and 1/2-2 inches below the die tip. The gas flow to thepicker unit is about 2000 SCFM, and stream is directed perpendicular tothe flow of the primary air. The velocity of the primary air is betweenabout 5 and 10 times the velocity of the secondary stream at the pointit is introduced. Superabsorbent particulates (Grain ProcessingCorporation Waterlock J-500 sodium polyacrylate superabsorbent) having aparticle size of about 150-200 microns are introduced at a pointslightly above the pulp nozzle from a tertiary air stream whose velocityis estimated to be between 1/5 and 1/10 the velocity of the primary airstream. The composite web is collected on a wire mesh belt, the belt isabout 16 inches below the extrusion die tip. The meltblown unit in whichsuperabsorbent is added is placed about 17 feet downstream from thefirst meltblown stream system and is identical to the first meltblownsystem except for not having the apparatus for addition ofsuperabsorbent. The composite layer not containing superabsorbentcomprises by weight about 70 percent cellulose fibers and about 30percent meltblown polypropylene microfibers. The layer containingsuperabsorbent comprises by weight about 25 percent superabsorbent, 52percent cellulose fiber, and 23 percent polypropylene microfibers. Theformation of the second layer that contains superabsorbent results in asecond layer of substantially the same thickness as the first layer thatdoes not contain superabsorbent. Therefore, the superabsorbent materialis located generally within the fiber interstices and does notsignificantly affect the bulk of the product. The composite product hasthe following measurements:

Basis Weight: 232 g/m²

Uncompressed Thickness: 0.200 inches

The web has a felt-like or cloth-like feel, was compressible andcushiony, and conformable and nonpapery. Further, when wet the productexhibits a nonclammy feel on the coform side while the side containingsuperabsorbent exhibits the clammy, slimy feel ofsuperabsorbent-containing materials. Further, it is found thatsubstantially all the superabsorbent applied to the process wasentrapped in the product as the dust collector does not exhibitsignificant collection of superabsorbent during layer formation.

We claim:
 1. A method of forming a nonwoven fabric-like material havinga unique combination of strength, absorbency and hand, said methodcomprising:A. forming at least one normal absorbency coform layer by thesteps of:(1) forming a primary air stream containing meltblownmicrofibers comprising generally discontinuous thermoplastic polymericmicrofibers, said primary air stream having a temperature in the rangeof from about 600° F. to about 700° F.; (2) forming a secondary airstream containing individualized staple fibers; (3) merging saidsecondary stream with said primary stream under turbulent conditions toform an integrated air stream containing a thorough mixture of saidmicrofibers and said staple fibers; and (4) directing said integratedair stream onto a moving forming surface to air-form a matrix of saidmicrofibers in which at least some of said microfibers are engaged bysaid individualized staple fibers to space the microfibers apart fromeach other, and said individualized staple fibers are disposedthroughout said matrix of microfibers and interconnected by and heldcaptive within said matrix by mechanical entanglement of saidmicrofibers with said staple fibers, the mechanical entanglement andinterconnection of said microfibers and staple fibers forming afirst-layer coherent integrated fibrous structure; B. forming at leastone highly absorbent layer by the steps of:(1) forming a second primaryair stream containing meltblown microfibers comprising generallydiscontinuous thermoplastic polymeric microfibers; (2) forming a secondsecondary air stream containing individualized wood pulp fibers; (3)forming a tertiary stream of superabsorbent particles; (4) merging saidsecond secondary stream and said tertiary stream with said secondprimary stream under turbulent conditions to form a second integratedair stream containing a thorough mixture of said superabsorbentparticles, said microfibers and said wood pulp fibers; and (5) directingsaid second integrated air stream onto said moving forming surfacecarrying said first layer to air-form second matrix of said microfibersin which at least some of said microfibers and said superabsorbentparticles are engaged by said individualized wood pulp fibers to spacethe microfibers apart from each other, and said individualized wood pulpfibers and said superabsorbent particles are disposed throughout saidmatrix of microfibers and interconnected by and held captive within saidmatrix by mechanical entanglement of said microfibers with said woodpulp fibers, the mechanical entanglement and interconnection of saidmicrofibers and wood pulp fibers forming a coherent integrated fibrousstructure, said first and second matrices being integrally connected andsaid first matrix acting to aid in trapping of any superabsorbent whichis not immediately extangled in said second matrix.
 2. The method ofclaim 1 wherein the steps 1-4 of Section A are repeated after onehighly-absorbent layer of Section B is formed.
 3. The method of claim 1further comprising placing a pervious web onto the forming surface priorto the steps of Section A.
 4. The method of claim 1 wherein air iswithdrawn from below the forming surface.
 5. The method of claim 1wherein after all layers are formed the material is embossed.
 6. Themethod of claim 1 wherein the layers are connected by intermingledfibers.
 7. A method of forming a nonwoven material comprising:A. formingat least one normal absorbency layer by:1. forming a first stream ofmeltblown microfibers,
 2. directing said stream of microfibers onto amoving forming surface to form a first layer, B. forming at least onehighly absorbent layer by the steps of:1. forming a second stream ofmeltblown microfibers,
 2. forming a stream of superabsorbent particles,3. merging said second stream of meltblown microfibers and said streamof superabsorbent particles to form an integrated stream containing amixture of meltblown fibers and superabsorbent,
 4. directing saidintegrated stream onto said moving surface carrying said first layer toform a second layer having superabsorbent particles disposed in a matrixof microfibers by mechanical entanglement said first and second layersbeing integrally connected and said first layer acting to aid intrapping of any superabsorbent which is not immediately entangled insaid matrix.
 8. The method of claim 7 wherein said first and secondlayers are connected by intermingled fibers.
 9. The method of claim 7wherein the steps 1 and 2 of Section A are repeated after onehighly-absorbent layer of Section B is formed.